Method and apparatus for spinning multicomponent fibers

ABSTRACT

A method and apparatus for spinning multi-component fibers from at least two different fiber forming spinning solutions. The solutions are extruded concurrently through a common orifice, being fed thereto through two narrow channels and into a common narrow channel. The thus formed composite stream is flowed through a continuous slit-like narrow channel which is separate from adjacent channels for other composite streams. The channel is sufficiently long so that the stream remains therein for at least 0.1 seconds. Thereafter the composite stream is extruded through a spinnerette to form composite filaments which do not delaminate.

United States Patent Nakagawa et al.

1*Jan. 14, 1975 METHOD AND APPARATUS FOR SPINNING MULTICOMPONENT FIBERSpatent subsequent to July 14, 1999, has been disclaimed.

Filed: Sept. 17, 1968 Appl. No.: 767,900

Related US. Application Data Continuation-in-part of Ser. No. 463,144,June 11, 1965, abandoned.

Assignee:

Notice:

Foreign Application Priority Data June 15, 1964 Japan 39-33823 US. Cl264/171, 264/168, 264/182, 425/131 Int. Cl. B29f 3/10, DOld 3/00 Fieldof Search 264/182, 117, 174, DIG. 26, 264/168; 425/131 References CitedUNITED STATES PATENTS 10/1934 Jacquet 117/52 3,038,236 6/1962 Breen264/171 3,195,865 7/1965 Harden I 25 /4 3,223,761 12/1965 Raley 264/1713,239,197 3/1966 Tollar 259/4 3,318,987 5/1967 Fitzgerald 264/1713,341,891 9/1967 Shimiza et a1. 264/D1G. 26 3,414,644 12/1968 Myles eta1. 264/168 3,416,982 12/1968 Petzetakos 264/171 X FOREIGN PATENTS ORAPPLICATIONS 1,365,873 5/1964 France i 264/D1G. 26

520,000 3/1955 Italy I 264/D1G. 26 39-26141 ll/l964 Japan 264/D1G. 26

Primary Examiner-Jay H. Woo Attorney, Agent, or FirmWenderoth, Lind &Ponack 57] ABSTRACT A method and apparatus for spinning multicomponentfibers from at least two different fiber forming spinning solutions. Thesolutions are extruded concurrently through a common orifice, being fedthereto through two narrow channels and into a common narrow channel.The thus formed composite stream is flowed through a continuousslit-like narrow channel which is separate from adjacent channels forother composite streams. The channel is sufficiently long so that thestream remains therein for at least 0.1 seconds. Thereafter thecomposite stream is extruded through a spinnerette to form compositefilaments which do not delaminate.

5 Claims, 4 Drawing Figures METHOD AND APPARATUS FOR SPINNINGMULTICOMPONENT FIBERS This application is a continuation-in-part ofapplication Ser. No. 463,144 filed June 11, 1965 now abandoned.

This invention relates to improvements in the production ofmulti-component, composite or conjugated fibers. More particularly, thisinvention relates to a method and apparatus for producingmulti-component fibers wherein two or more different components arelaminated or conjugated longitudinally of the fibers with an interfaceof junction area therebetween wherein these different components aresufficiently intermingled with or diffused into each other.

It is well known to produce multi-component fibers from at least twodifferent fiber-forming spinning solutions by extruding themconcurrently through a common orifice. Due to the difference in thermalshrinkage or swelling between these different materials of which suchfibers are produced, coily crimps can be devel oped therein.

These known multi-component fibers, however, have the drawback that thecomponents tend to be peeled off or delaminated. This tendency is morepronounced when the physical and chemical properties of the componentsare more different in order to improve the crimping characteristics.When the fiber components are thus peeled off or delaminated, thecrimping characteristics are lost and the appearance of the finishedproduct made of such fibers is adversely affected.

Therefore, it is an object of this invention to produce composite fiberswherein two or more components conjugate together firmly without dangerof delamination thereof.

It has been found that this object is accomplished, according to thisinvention, by providing an intermediate orjunction area between thedifferent components, the components being sufficiently intermingledwith or diffused into each other in said intermediate or junction area.It is difficult to determine the exact area of such an intermediate orjunction portion, but it has been found only a very small area, such aspercent or less ofthe total cross sectional area of the fiber, issufficient to substantially prevent the delamination of the components.

It has also been found that the necessary intermediate or junction areacan be formed by interfacially contacting a spinning solution for onefiber component with another spinning solution for another fibercomponent in longitudinal laminations and maintaining the contact for asufficient period of time before the solutions are concurrently extrudedthrough spinning orifices for coagulation or solidification so thatthere occurs the desired intermingling or mutual diffusion in theinterfacial (intermediate) or junction area. During the contact it ispreferable to maintain the temperature as high as possible. For example,when the spinning solution is an aqueous solution, it is maintained at atemperature of 7090C.

It is believed that this blending of different spinning solutions at thenarrow interfacial or junction area in the boundary area of thesolutions is caused by thermal mutual diffusion between the molten ordissolved polymers, and therefore a prolonged period of contact of thesolutions is most effective in producing the desired intermediate orjunction area.

The period of time for keeping the interfacial contact of the spinningsolutions required for producing the desired intermediate or junctionarea varies, depending upon the particular temperature of the system,polymer concentration and viscosity of the spinning solutions used.However, it has been found that the period of time of contact should belonger than 0.1 second, more preferably longer than 0.2 second.

To adjust the period of contact between the spinning solutions, thelength of the spinnerette orifice can be altered. However, asufficiently long orifice causes an unduly high back pressure. Moreover,as the volumes of the solutions being extruded are increased, the periodof contact is reduced, and, consequently, the components are liable tobe peeled off. And this problem of back pressure can not easily besolved simply by modifying the spinnerette orifice. The back pressureagainst the nozzle can be controlled to some extent by employing aspecially designed spinerette orifice. Stated differently, only thedischarge end of the orifice can be made the conventional size, and thediameter of the remaining portion of the orifice increased. For thispurpose, however, there must be provided an additional variety ofspinnerette orifices.

Thus, according to this invention, there is provided a spinningapparatus which comprises means for separately supplying a plurality ofdifferent spinning solutions, narrow channels for receiving each of saidsolutions, said narrow channels merging into a common narrow channelcommunicating with another slit-like narrow channel, said slit-likenarrow channel receiving said solutions and communicating with orificesand being of such a length, in respect of the flow of said solutions,that the solutions are kept in contact for a sufficient time to form anintermediate area in the boundary layer of said solutions, wherein thesolutions are sufficiently intermingled or mutually diffused, prior tobeing extruded through said orifices. In order that the lack of pressurenot be unduly high, the width of the common narrow channel is from 5-10times the diameter of the orifices.

The invention will be described in more detail by referring to theaccompanying drawings wherein:

FIG. 1 is an exploded perspective view, partly broken away, of anembodiment of a device according to this invention, with variouselements being disassembled;

FIG. 2a is an enlarged cross section, schematically represented, of thefiber showing delamination thereof;

FIG. 2b is a view similar to FIG. 2a, but showing another state ofdelamination; and

FIG. 3 is a view similar to FIG. 20, but showing the fiber of thisinvention having an intermediate or junction area.

Referring to FIG. 1, there is illustrated a spinning device forproducing bi-component fibers according to this invention whichcomprises a plurality of partition walls 1 defining narrow longitudinalchannels 2 within a cylindrical sleeve 3. The lower end portion of eachpartition wall is tapered to a V-shaped edge as shown. The inlet sectionof the cylindrical sleeve 3 is provided with a baffle 4 which serves todivide the inlet section into two chambers 5 and 6. One spinningsolution is supplied to the chamber 5 while the other is supplied to thechamber 6. The arrangement is such that the channels 2 are suppliedalternately with these two different spinning solutions.

In association with the lower end of the sleeve 3 there is provided aguide plate 7 which has a corresponding number of Y-shaped channels 8.When assembled, each V-shaped edge of the partition wall 1 extends intothe upper V-shaped groove of the corresponding channel 8 on the plate 7defining a V-shaped channel merging into a straight channel portion 9 ofthe Y-shaped channel 8. The narrow straight channel 9 communicates withcorresponding slit-like narrow channel 14 of guide disc 13. Saidslit-like narrow channel 14 communicates with the corresponding orifices10 of spinnerette 11, which is held in a cap assembly 12.

In operation, two different spinning solutions are supplied to theseparate chambers 5 and 6, respectively, and then forced into thechannels 2 through which the solutions flow downwardly. At the top ofthe V-channel defined by the V-shaped edge and the upper V-shaped grooveof the channel 8, the two different solutions are merged and flowtogether into the straight channel 9 in laminar flow with the adjacentfaces of thin films of different solutions in interfacial contact; Thenthe solutions continuously and concurrently flow down through saidslit-like narrow channel 14 and are extruded through the common orifices10 into a conventional coagulating bath (not shown) wherein composite orconjugated fibers are formed. The construction and function of aspinning device of this type is more fully described in US. Pat. No.3,182,106 of May 4, 1965, and reference should be made to the US Patentfor further details.

The important feature of this invention resides in modifying, inrelation to the flow rate of spinning solution, the said straightchannel portion 9 so that the spinning solutions remain therein longenough to allow sufficient intermingling or mutual diffusion of thedifferent solutions during the passage therethrough prior to extrusionthrough the orifices 10. As in the case where the flow rate of thespinning solutions is high, an intermediate guide disc 13 having aplurality of slit-like narrow channels 14 corresponding to andcommunicating at the upper end with the corresponding straight channels9 and at the lower end with the corresponding orifices I0 is arranged toobtain a desired length of the channels 9 and 14 necessary for producingthe required intermingling or mutual diffusion of the solutions. Theintermediate guide disc 13 may be made of a plastic or rubber materialresistant to heat and chemicals.

In addition, a further important feature of the present invention is inproperly dimensioning the common narrow channel so as to overcomevarious disadvantages of an incorrect back pressure in the interminglingor mutual diffusion area of the different spinning solutions, whichproper dimensioning prevents the peel-off on delamination of fiberforming materials while retaining at least 0.1 second of contact time ofsaid solutions to form an interfacial or junction area therebetweenahead of the spinnerette orifices.

This further important feature comprises making the dimensions of thepassages for the spinning solutions and the orifices in the relationwherein d is the minimum diameter of the spinnerette orifices and D isthe width of the common narrow channel communicating with said orifices,and adjusting the thickness of the guide plate and/or guide disc to givethe required contact time for the volumes of the spinning solutionsflowing therethrough.

[n the present invention, if the slit width is less than theabovementioned range, the back pressure of the spinning solution will beincreased greatly and it will make it impossible to continue thespinning process.

On the contrary, if the slit width is wider than the said relation, nolaminar flow of the spinning solution in the common narrow channel willbe produced and the re sulting spun fibers will not have high resistanceto delamination.

This invention will be further described in detail by way of thefollowing examples, it being understood, however, that the scope of theinvention is by no means limited thereto. All parts are by weight.

EXAMPLE 1 Two spinning solutions were prepared, respectively, from acopolymer A (intrinsic viscosity: 1.5 in DMF) consisting of parts ofacrylonitrile and 10 parts of methyl acrylate and a copolymer B(intrinsic viscosity: 1.5 in DMF) consisting of 87 parts ofacrylonitrilc, l3 parts of methyl acrylate and 0.5 parts of sodiumallylsulfonate by dissolving each polymer in a 45 percent aqueoussolution of sodium thiocyanate to obtain a solution of 10 percent byweight. The spinning solutions prepared as above were then fed at apredetermined rate to the equipment shown in FIG. 1, but not having anintermediate disc 13, and extruded in a coagulating bath comprising a 10percent (by weight) aqueous solution (3C.) of sodium thiocyanate. Thespinning solutions were maintained at a constant temperature of 80C.,and the viscosity of each solution was 1,500 cp at that temperature.

The plate '7 used in this example had four channels, each straightchannel 9 measuring 1 mm. in width and 1.3 mm. in depth. The spinningsolutions after being merged were retained in the straight channel for avarying period (see Table l), and extruded through a spinnerette havinga varying number of orifices so as to ob tain filaments of the samedenier number. While the orifiees had a varying diameter from 1 mm. to0.09 mm., the retention time of the solutions within the orifices wasnegligible.

The coagulated filaments were taken up at a rate of 50 meters perminute, and then washed with water thoroughly to remove the solvent. Thewashed filaments were stretched 10 times their initial length in hotwater and dried over drying rollers, whereby 3-denier filaments wereobtained.

To ascertain how the two components had been conjugated, the dryfilaments prepared above were dyed with 4 percent (relative to fiber) ofAizen Cathilon Black (a cationic dyestuff by Hodogaya Chemical Co.,

Ltd.) in the conventional manner. Then, the dyed filaments were treatedwith saturated water vapor at C. for 20 minutes so as to allow the dyeto diffuse sufficiently into the fiber structure, and the crosssectionof each filament was studied under a microscope.

TABLE 1 Flow rate of spinning solutions (cc/min.) I5 30 45 60 75 Numberof orifices 12 24 36 48 60 Contact time (sec) 0.42 0,2l ().l4 0.11 0.083Delamination None None Partially Partially Almost all FIGs. 2a and 2beach shows the cross-section of the filament obtained by feeding thespinning dope at a rate of 75 c.c. per minute. It will be apparent thatthe two components are separated into two distinct sections, one of alighter shade and the other of a darker shade, evidently showingdelamination at the interface.

It may be concluded from the results of Table 1 that, in order toprevent such a delamination of the two components, the period of contactof the two spinning solutions before extrusion through orifice should belonger than 0.1 second and more preferably longer than 0.2 second.

EXAMPLE 2 The procedure of Example 1 was repeated with the exceptionthat an intermediate guide plate 13 was made of Teflon sheet. Thespinning solutions were extruded at a rate of 75 c.c. per minute. Thethickness of the Teflon sheet was 6 mm. and the width of each channelwas 1 mm. The intermediate guide plate 13 served to prevent leakage ofthe spinning dope between the spinnerette 11 and plate 7 and provided anadditional retention time of 0.38 second for the contacted spinningsolutions. The resulting filament was dyed in the same manner as Example1, and the dyed filament microscopically studied. The cross-section ofthis filament is shown in FIG. 3, which indicates that the twocomponents are firmly joined through an intermediate area where the twocomponents are sufficiently intermingled.

What is claimed is:

l. A method of spinning multi-component fibers from at least twodifferent fiber-forming spinning solutions by extruding themconcurrently through a common orifice to produce a composite stream withthe parts in interfacial contact, then flowing the thus formed compositestream through a continuous substantially uniform cross-section channelwhich is separate from adjacent channels for other streams of spinningsolution for at least 0.1 second, said time being sufficient so thatthere is formed in the boundary layer of said spinning solutions, anintermediate area wherein the spinning solutions are sufficientlyintermingled and diffused in each other to firmly join the differentcomponents in subsequently extruded filaments and thereafter extrudingthe composite stream through an orifice to form composite filaments.

2. A method as claimed in claim 1 wherein the contacting time is atleast 0.2 second.

3. A method as claimed in claim 1 wherein the spinning solutions aremaintained at a temperature of 90C. when the solutions are aqueoussolutions.

4. An apparatus for spinning multi-component fibers from at least twodifferent fiber-forming spinning solutions which comprises means forseparately supplying a plurality of different spinning solutions, twonarrow channels connected to the means for supplying the spinningsolutions and respectively receiving the respective solutions, a commonnarrow channel into which said two narrow channels merge. anothersubstantially identical and uniform cross-sectional dimension slit-likenarrow channel into which said common narrow channel opens, saidslitlike narrow channel receiving said solutions, and a spinnerette haveorifices at the ends of said slit-like narrow channels and into whichsaid slit-like narrow channels open directly, said slit-like narrowchannels having a width I) in a relation to the minimum diameter d ofthe spinnerette of whereby said solutions are kept in interfacialcontact for a period of at least 0.1 second so as to form anintermediate area in the boundary layer of said solutions wherein thesolutions are intermingled and mutually diffused prior to being extrudedthrough said orifices.

5. An apparatus as claimed in claim 4 in which said apparatus has areplaceable member in which said slitlike narrow channels are presentwhereby the member can be replaced with a like member of different sizeto change the length of the slit-like narrow channels.

2. A method as claimed in claim 1 wherein the contacting time is atleast 0.2 second.
 3. A method as claimed in claim 1 wherein the spinningsolutions are maintained at a temperature of 70*-90*C. when thesolutions are aqueous solutions.
 4. An apparatus for spinningmulti-component fibers from at least two different fiber-formingspinning solutions which comprises means for separately supplying aplurality of different spinning solutions, two narrow channels connectedto the means for supplying the spinning solutions and respectivelyreceiving the respective solutions, a common narrow channel into whichsaid two narrow channels merge, another substantially identical anduniform cross-sectional dimension slit-like narrow channel into whichsaid common narrow channel opens, said slit-like narrow channelreceiving said solutions, and a spinnerette have orifices at the ends ofsaid slit-like narrow channels and into which said slit-like narrowchannels open directly, said slit-like narrow channels having a width Din a relation to the minimum diameter d of the spinnerette of 5d < or =D < or = 10 d whereby said solutions are kept in interfacial contact fora period of at least 0.1 second so as to form an intermediate area inthe boundary layer of said solutions wherein the solutions areintermingled and mutually diffused prior to being extruded through saidorifices.
 5. An apparatus as claimed in claim 4 in which said apparatushas a replaceable member in which said slit-like narrow channels arepresent whereby the member can be replaced with a like member ofdifferent size to change the length of the slit-like narrow channels.